Restricted Novel Heat Treatments for Obtaining High Jc in Nb- 46.5 WT.%Ti: II. Prestrain Dependence
In an earlier study, minimal initial heat treatments (3hr/300C) after a large cold work drawing strain (εp=6.37 and 7) were found to be very successful in providing nucleation sites for triple-point α-Ti precipitation during a final full heat treatment (80hr/420C). The minimal heat treatment schedules were repeated and expanded upon in this study but with a cold work pre-strain of only 5. The lower pre-strain reduced the effectiveness of the minimal heat treatment schedules resulting, typically, in a 25% reduction in precipitate volume and in Jc. The Jc and volume % α-Ti values, however, remained remarkably high considering the minimal level of heat treatment and over 2800Amm −2 was achieved at 5T, 4.2K with only one conventional heat treatment (160hr/420C).
KeywordsHeat Treatment Critical Current Density Final Strain Final Heat Treatment Conventional Heat Treatment
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